/Engine/Source/Developer/MeshBoneReduction/Public/MeshBoneReduction.h
Get Bones To Remove from the Desired LOD List of bones to remove should containstrue if any bone to be replaced
bool GetBoneReductionData ( const [USkeletalMesh](API\Runtime\Engine\Engine\USkeletalMesh) * SkeletalMesh, int32 DesiredLOD, [TMap](API\Runtime\Core\Containers\TMap)< FBoneIndexType, FBoneIndexType > & OutBonesToReplace, const [TArray](API\Runtime\Core\Containers\TArray)< [FName](API\Runtime\Core\UObject\FName) > * BoneNamesToRemove )